Mix a packet of active yeast with ¼ cup of warm water and a tsp of sugar in a bowl. After 10 minutes, your child will see the mixture foaming--a sign that the microbes are feeding and producing carbon dioxide. Talk about the role those CO2 bubbles play in making dough rise!

Experiment

What happens when you leave out the sugar? (Hint: organisms like yeast need to eat sweet stuff to multiply.) After you’ve baked your bread, see if your kiddo can spot the connection between the foaming yeast and the air pockets in a slice. (Then butter it, and snack!)